Characterization of Metal Concentrations in PM2.5 and PM10-2.5 in Rural and Urban Colorado

The Colorado Coarse Rural Urban Sources and Health (CCRUSH) study is a three-year study focused on characterizing the mass, composition and sources of coarse particulate matter (PM_10-2.5) in urban and rural Colorado and evaluating how differences may be associated with several health outcomes. As part of this study, ambient air samples were collected every sixth day for twenty-four hours from four sites in Denver and Greeley, Colorado from February 2010 to March 2011 to study the chemical composition of PM_10-2.5. The two sites in Denver were Alsup and Edison Elementary School. Edison is an urban-residential site located west of Downtown Denver while Alsup is an industrial-residential site. The two sites in Greeley were McAuliffe and Maplewood Elementary School. Both are residential sites. Greeley is the county seat of Colorado's most prolific agricultural region. Samples were collected on Teflon filters at each of these locations using a dichotomous filter sampler. Multiple filter samples for each site, usually from the same month, were combined and analyzed for 49 elements in fine particulate matter (PM_2.5) and PM_10-2.5. The monthly composites were analyzed by Magnetic Sector Inductively Coupled Plasma-Mass Spectroscopy (SF-ICP-MS). Crustal enrichment factors (CEF) were calculated to assess the contributions of anthropogenic and geogenic sources of trace elements on PM_10-2.5 emissions. Principal Component Analysis (PCA) will be used to identify sources.